The field of the present invention relates generally to the manufacture of 3-D glasses.
Three-dimensional movies made their first appearance in movie theaters in the 1950's. When such movies were introduced, patrons of the theaters were given special glasses which would create a three-dimensional viewing effect, and these glasses came to be known as "3-D glasses" within the industry. Since the early introduction of 3-D glasses, the process by which a three-dimensional viewing effect is achieved has undergone several changes. However, despite these changes, the term "3-D glasses" still remains in use and the term connotes glasses which are used to view specially prepared printed materials, films and the like. When a person wears a pair of these glasses, the pair of lenses will interact with the specially prepared materials to give the appearance of a three-dimensional effect.
3-D glasses today are typically constructed of a cardboard frame which houses two lenses. The lenses in at least some of the existing processes are made from a material which shifts the field of polarization of the viewer's eye. The major expense associated with the cost of such 3-D glasses is the lens material, the labor required to produce the glasses being another major expense.
At the present time, 3-D glasses are manufactured by taking pre-printed sheets or stiff cardboard, typically 10 to 12 point, die-cutting these sheets for the eyeholes, applying glue to one of the sheets, laying on two strips of lens material cut at 45.degree. from a roll of lens material, laying the two strips of lens material which shift polarized planes of light at opposite angles on one of the sheets and then laminating the two sheets together. These sheets are then die-cut into a final form.
The final shape of the eye openings in the glasses of the prior art tends to be rectangular since the lens material applied to the cardboard will be in the shape of a long rectangular strip. However, there is considerable waste in this system; especially in the lens material. Initially, the rectangular lens shape does not conform to the shape of the human eye, so excess material in the rectangular corners will be wasted. Further, the rectangular sections of lens material which are formed between pairs of glasses by die cutting the strip to form the glasses are not utilized. Accordingly, when the square lens eye openings, the rectangular tabs leftover between the die-cut glasses and the extra border required for gluing and cementing the lens material in place are taken into account, up to 35% of the lens material will be wasted. And since the major expense in the cost of a pair of 3-D glasses is the lens material, such a large percentage of waste significantly contributes to the overall cost of a pair of 3-D glasses.
Accordingly, there exists a need to reduce the waste consumption of lens material utilized in the manufacture of 3-D glasses. Additionally, there also exists a need to reduce the cost of the manufacture of 3-D glasses by reducing or eliminating the labor intensive steps utilized in current manufacturing processes.